IMO, metic has a flaw that should be addressed in using the gram as a standard unit, and I'm hardly alone in this opinion. It's too small for the average human to have a feel for it. The kilogram is the more intuitive unit for most people.
Just to point out - in SI units the kilogram is the base unit of mass, not gram :)I'm not exactly sure what you mean by "standard unit".. if gram is too small just say it in kilograms?